I have been driving around with my new Injen exhaust for a few days now and am getting a better feel for it in terms of performance and sound so I figured I would post an initial review.
Craftsmanship/Build Quality: the welds and build quality is top notch with even welds all around the exhaust with no splatter. The pipes are all polished well and the exhaust fit perfectly first try with no surprises. The only thing I wish was that the Y pipes did not have two 90 degree bends on either side as there is plenty of space to allow for smooth bends.
Sound: The sound is incredible. It is extremely deep, smooth, and exotic which is exactly what I was looking for. It is not overly loud but it definitely makes itself known. I smile every time I take it out because every time I touch the throttle, people all turn and look even if they are in their cars which is a great feeling. However, one issue I have is that there is some serious drone around 2,000 rpm. I am not that sensitive to drone or loud exhausts since my Saab was pretty loud but the drone is too much for me and is prevalent from 2-3krpm. I will be dealing with this with a set of Helmholtz resonators (branch resonators) that will be custom installed in the coming weeks to tune out the worse of the drone around 2,000 rpm without affecting the sound or volume of the exhaust (a major concern for me as I love it other than the drone).
Performance: I have become pretty good at feeling whether or not any power is picked up with these types of mods as I don't expect anything and can only be pleasantly surprised it gains are felt. I noticed power and torque gained with the first WOT pull I did, but more importantly the low end power has improved as the car is more willing to pull from low rpms. This is a big bonus but I obviously cannot tell of any proven gains until I get the car on a dyno.
In conclusion, I really love this exhaust and it fits the exact sound and look I was going for. Once the drone is finished, I believe this exhaust setup will be perfect! I will get some more video soon, but for now here is a cold start and a 3krpm rev: